Question 1

An extrasolar planet is

Accepted Answer

An extrasolar planet is a planet found orbiting around a star other than the sun. It is also known as an exoplanet.

Question 2

The hydrogen in our solar system was created from subatomic particles in

Accepted Answer

The hydrogen in our solar system was created during the Big Bang, the event that marks the beginning of the universe. During the first few minutes after the Big Bang, the simplest elements, including hydrogen, helium, and traces of lithium, were formed through a process known as nucleosynthesis.

Question 3

After the first solid grains formed in our solar system, these particles could then grow by the process of ____, the collision and sticking of one particle with another to continue the formation of planetesimals. Each of these has many atoms or molecules.

Accepted Answer

Accretion refers to the collision and sticking of particles to form larger objects. This is the process by which planetesimals formed in the early solar system.

Question 4

The hydrogen and helium in our solar system were created from subatomic particles about ______ years ago.

Accepted Answer

The hydrogen and helium in our solar system were created from subatomic particles about 14 billion years ago, during the Big Bang, which is the event thought to have originated the universe.

Question 5

____ are located beyond the asteroid belt (3 AU) from the sun, have extremely large masses and very low densities.

Accepted Answer

Jovian planets, also known as gas giants, are located beyond the asteroid belt, have large masses (much more massive than terrestrial planets), and low densities due to their gas and/or liquid composition.

Question 6

Which one of the following IS NOT a characteristic of terrestrial planets?

Accepted Answer

Terrestrial planets, such as Earth, Mars, Venus, and Mercury, have high average densities due to their rocky, metallic compositions. Therefore, option A is not a characteristic of terrestrial planets.

Question 7

Accretion is

Accepted Answer

Accretion refers to the process of adding material to an object, and in this context, it typically refers to the collection of solid particles (such as dust or ice) to form larger objects like asteroids or planets. Option A is also correct but less specific – adding material atom by atom can occur through various processes such as chemical reactions, but it's not necessarily the most common meaning of accretion in astronomy. Options C, D, and E are not related to the definition of accretion.

Question 8

A future news release might report that a new planet has been found around a star very similar to our sun. This newly discovered planet is claimed to have a mass 40 times that of Earth and is located nearly 25 AU from the star it orbits. Which of the following would be a reasonable prediction about this planet?

Accepted Answer

The answer of A future news release might report that...

Question 9

The Jovian problem refers to

Accepted Answer

The Jovian problem refers to the apparently short period of time that disks exist around stars from which Jovian planets can form. This is because the formation of gas giant planets like Jupiter and Saturn requires a large amount of gas and dust, which is present in protoplanetary disks around young stars. However, these disks are thought to dissipate within a few million years, which is a relatively short period of time compared to the age of the universe. This raises the question of how these planets could have formed in such a short amount of time, which is known as the Jovian problem.

Question 10

A newly formed planet or large asteroid becomes molten due to

Accepted Answer

Both infalling objects and the decay of radioactive element isotopes can generate enough heat to cause a newly formed planet or large asteroid to become molten. This is due to the potential energy released during the infalling process or the heat generated by radioactive decay. As a result, both factors could play a role in the formation of a molten planet or asteroid.

Question 11

The iron in our solar system was created from smaller-mass atomic nuclei in

Accepted Answer

Iron is created in supernovae, where smaller-mass atomic nuclei fuse together under extreme pressure and temperatures.

Question 12

Outgassing is

Accepted Answer

Outgassing refers to the release of gas from rocks as they are heated, typically during volcanic eruptions or when rocks are melted in a laboratory setting.

Question 13

A(n) ____ is a solar-system object that enters Earth's atmosphere and becomes very hot due to friction between the object and Earth's atmosphere and does not survive to reach the surface.

Accepted Answer

A meteor is a solar-system object that enters Earth's atmosphere and becomes very hot due to friction between the object and Earth's atmosphere and does not survive to reach the surface. Option A is incorrect because an asteroid is a solid, rocky or metallic object that orbits the Sun. Option C is incorrect because a comet is a mixture of ice and dust that generates a coma (a fuzzy atmosphere) and often a tail when it approaches the Sun. Option D is incorrect because a meteoroid is a small rocky or metallic body that travels through space, while a meteor is a meteoroid that has entered Earth's atmosphere and is seen as a streak of light. Option E is incorrect because a planetesimal is a building block of planets, typically a few kilometers in diameter, that formed from the solar nebula.

Question 14

Which one of the following IS a characteristic of Jovian planets?

Accepted Answer

Jovian planets, also known as gas giants, have a low average density compared to terrestrial planets because they are primarily composed of gas and ice rather than solid rock.

Question 15

The first small solid grains or flakes formed in our solar system by the process of ____, the addition of material to an object an atom or molecule at a time.

Accepted Answer

The process described, of adding material to create small solid grains or flakes, is known as condensation. Accretion involves the accumulation of these small grains into larger objects, while sublimation, hydration, and vaporization do not involve the creation of solid particles.

Question 16

The oldest rocks found on Earth are about ____ years old.

Accepted Answer

The oldest rocks found on Earth are about 3.9 billion years old.

Question 17

____ pushed gas and dust particles out of the solar nebula by the light from the sun.

Accepted Answer

Radiation pressure refers to the force exerted by photons of light. In the early solar system, the sun was surrounded by a large cloud of gas and dust called the solar nebula. Radiation pressure from the sunlight caused the gas and dust to be pushed away from the sun, creating a clear zone in the center known as the protosun. This process is thought to have played a key role in the formation of the planets and other bodies in the solar system.

Question 18

The first solid grains of ______ formed in hot regions near the sun. Much farther from the sun the first grains (or rather flakes) of ________also formed by a similar process as the close-in grains, the process of _______.

Accepted Answer

The first solid grains of iron formed in hot regions near the sun, while much farther from the sun, the first grains of water ice formed. Both processes are examples of condensation, where gas turns into solid particles.

Question 19

____ is the separation of material in a newly formed planet or asteroid according to density. This happens when the object becomes molten.

Accepted Answer

Differentiation is the separation of material in a newly formed planet or asteroid according to density. This happens when the object becomes molten. Accretion refers to the process of particles coming together to form a larger object, condensation is the process of a gas turning into a solid, outgassing is the release of gases from a planetary body, and sublimation is the process of a solid turning directly into a gas.

Question 20

Protoplanets

Accepted Answer

Protoplanets grew in size by the collision and coalescing of planetesimals. Accretion and condensation were important processes, but the primary mechanism for growth was the gradual build-up of planetesimals through collisions and their subsequent merger to form larger bodies. The terrestrial planets formed from protoplanets through a process of continued evolution and differentiation. The collection of particles in the solar wind was not a significant factor in the growth of protoplanets.

Quiz 15: The Origin of the Solar System